Ten years of arguing with books

Threatened Bees and Threatened Science (Reply)

Nov 2015A Sting in the Tail - Dave Goulson - Jonathan Cape, 2013 (Kindle edition)* * * * *It says a lot for the basic decency of my next-door neighbours that we are still on speaking terms, given that we have diametrically opposed views on what constitutes a good back yard. They have recently turned theirs into a wall-to-wall paved patio with an admittedly attractive sun motif but not a green shoot in sight. My garden, on the other hand, is messy and weedy, with unkempt lawns that are only fifty percent grass and plants with a tendency to grow like topsy until I get around to pruning them back. There is a reason for my neglect, which is that I am trying to make my garden a resource for wildlife in general, and in particular for my favourite insect, the bumblebee. I consider it a real achievement that last year I had a nest of them under my rotting garden shed, though it was rather alarming to see them drifting around the doorway in a vaguely threatening manner when I went to get out the lawnmower.

My enthusiasm, however, is as nothing compared to that of Dave Goulson, who has not only made a career of studying bumblebees but has founded the Bumblebee Conservation Trust to promote them. I knew that we would get on when he mentioned Gerald Durrell's Corfu Trilogy as one of his formative influences, and his writing style is similarly autobiographical and occasionally laugh-out-loud funny. Unlike Durrell however, Goulson is an academic and brings a scientist's rigour and clarity to his descriptions of bumblebee life and its many mysteries.Bumblebees are so common that is easy to forget what extraordinary creatures they are (and let us ignore the still depressingly common urban myth that "according to science", they are not aerodynamic enough to fly). Like homing pigeons, they can navigate back to their nests from long distances away (Goulson has shown - by releasing bees with coloured disks on their backs - that their maximum range is about 10 kilometres). How do they do this? By taking long, looping exploratory flights, during which they memorise landmarks and locate good sources of food.

The book is full of such insights into bee behaviour and the ingenious and often slightly absurd experiments that scientists come up with to explain them. My favourite bit of research derived from an observation that bees preferentially visit comfrey flowers that have full reservoirs of nectar and avoid those that don’t. Finding out how they did this took a four year PhD. None of the obvious explanations - they smell the nectar, some subtle visual clue from the flowers - turned out to be true. In fact the bees could readily be fooled into visiting flowers from which the nectar had been artificially removed with a tiny pipette. The eureka moment which came, according to Goulson "after a lot of pondering", was to realise that the bees weren't detecting the presence of pollen, but recent visits by other bees. The proof for this came from a bizarre experiment in which the feet of bees were washed in a solvent which was pipetted onto nectar-laden flowers, which were duly avoided. Bees, it seems, can detect other bees' smelly feet. However, that isn't the end of the story. The bees can detect the age of footprints and have different avoidance periods for different species of plant corresponding to their differing nectar reservoir refill times. We still don't know how they do this - the large molecules making up the waxy coating of insect feet does not readily evaporate, so the relative strength of the smell cannot be the explanation.

Spending four years washing bees' feet may seem like a good candidate for an Ig Nobel award, but this optimisation of foraging behaviour turns out to be common to many pollinating species and vital to their effectiveness. As bumble bees are responsible for much of the two thirds of the pollination of food crops that is not done by honey bees, understanding their strategies is vital to their conservation and our diets. Goulson's work, mad as it may seem, is important.

And it's not just about conserving bumblebees. For in some circumstances, they can be a menace. Not, I hasten to add, through any undesirable behaviour of their own, but through the actions of humans. Tasmania, which had no native bumblebees, mysteriously acquired some from New Zealand in 1992 (Goulson points out that research showing that bumblebees are fantastic pollinators of tomato plants was published in the late 80s and leaves us to draw our own conclusions about what Australian tomato growers may or may not have been up to). Goulson researched the possible negative effects. The good news was that the incidence of native bees and other pollinators was unaffected. However, the invaders did seem to be responsible for an increase in the fertility of tree lupins, enabling them to infest coastal areas and crowd out other scrubland plants. Yet another lesson, as if any more were needed, in the inadvisability of introducing species to areas where they are not native.

Of course, reintroducing bumblebees in places where they were formerly found is another matter, and the final chapter covers a project to do just that in the UK. The short-haired bumblebee was declared extinct in this country in 2000, having not been seen since 1988. The plan was originally to use New Zealand bees, which would have had a pleasing symmetry as they were introduced there from the UK in the nineteenth century, but they proved to be too inbred, so Swedish stock was used instead. At time of writing Goulson was uncertain whether the reintroduction had been successful, but recent news is encouraging.

Needless to say, I loved this book. Goulson himself is as charming and charismatic as the animals that he describes, and the research he is doing is both proper science and important to our well-being. Sadly it requires international collaboration and is therefore precisely the sort of research that is threatened by Brexit. Let us hope that the short-haired bumblebee manages to establish itself before the inevitable cut in funding.